The modern telecommunications business customer has available an array of telephone services aimed at providing alternative ways of providing toll telephone service. Among the various alternatives available are private networks, private tie lines and trunks, foreign exchange services, wide area telephone services such as INWATS, and direct distance dialing over the public network. Many business customers attempt to minimize their telephone costs by purchasing a combination of these services in accordance with their needs. In addition, commercial devices are available which attempt to minimize the cost of using the various facilities and services a customer may have purchased by automatically routine calls via the cheapest route. These devices are typically called WATS boxes. While WATS boxes work well for any given configuration of services, because of the complexity involved in evaluating the merits of alternative configurations for certain customers under varying conditions, it is often difficult to determine in the first instance if a configuration is in fact the most economical for a customer's needs.
In addition, once a configuration of services is selected, it is usually excessively expensive and wasteful to provide sufficient dedicated facilities in the configuration to adequately handle peak traffic loads. Conversely, poor service may result during peak traffic periods if minimum facilities are purchased by a customer.
Attempts have been made to solve these problems by providing arrangements whereby overflow calls on private networks and the like are switched onto the public network. Such an arrangement in a private network is disclosed in U.S. Pat. No. 3,150,236, which issued to J. W. Gorgas on Sept. 22, 1964. According to the patent teaching, in addition to the charge for private network services, a record of a call spilling over from the private network to the public network is made in the office where the spillover occurs so that the customer may be additionally billed for the call portion on the public network.
U.S. Pat. No. 3,157,743, which issued to R. C. Avery on Nov. 17, 1964, discloses an improvement to the above call spillover arrangement. The Avery improvement provides a centralized record of call data pertaining to calls diverted from a private network to the public network. This substantially improves the billing aspects of call spillover.
U.S. Pat. No. 3,188,396, which issued to G. F. MacFarlane on June 8, 1965, discloses an arrangement which attempts to improve the efficiency of foreign exchange service by sharing toll facilities for both ordinary toll traffic and foreign exchange calls.
Although the above arrangements are useful, the provision of same to customers in conjunction with private facilities remains costly to telephone companies and, therefore, to customers. This is caused, in part, by the fact that private facilities can only be accessed from specific locations predefined by the customer.
In view of the above, it is apparent that a need exists to reduce the cost of providing private facilities, to simplify the procedure by which a customer may tailor its telephone services to assure cost minimization, and to further improve dedicated facility service.